In the field of vertebroplasty, a composition for supporting vertebral bone is injected into or around bone, e.g. by filling and/or covering internal or external cracks, holes or deteriorations in the natural tissue, so as to support the bone itself and/or surrounding tissue. Compositions such as bone cements of various ingredients are loaded into a syringe and injected through a needle and/or tubing to the bone or other site where the composition is desired. When an adequate volume of composition has been deposited, the injection(s) cease and the syringe (and needle and/or tubing if appropriate) are removed.
Generally, a number of different parts are required for preparing and injecting the composition. Compositions have been created in which a solid component (e.g. powdered cement or granulated polymer) is mixed with a liquid monomer to create the injectable composition. The solid and liquid components are combined in a mixing bowl or cup. When the injectable composition is ready, it is removed from the mixing bowl and placed in a syringe that is or will be connected to a tube or needle placed in the patient. The syringe plunger is then pressed to deposit the composition at the vertebroplasty site.
For example, kits featuring the Minimix and Duro-Ject devices sold by Cook Incorporated provide structure needed for vertebroplasty. A solid component is poured into the Minimix device, and a liquid monomer component is added. The components are mixed in the device for a period of time sufficient to develop a cement composition of appropriate homogeneity. A floor of the Minimix device is dropped below the level of an outlet port, and a syringe is connected to the outlet port. Drawing the syringe's plunger out fills the syringe with cement composition. The syringe is disconnected from the outlet port and is connected to another syringe or injector barrel without a plunger (via a stopcock in one example), and pushing in on the filled syringe's plunger moves cement composition from the syringe through the stopcock and into the injector barrel. The injector barrel is then disconnected from the stopcock and connected to a base of the Duro-Ject device, which has a threaded plunger for insertion into the injector barrel. Tubing that leads or will lead to the vertebroplasty site is connected to the other end of the injector barrel, and turning the threaded plunger forces cement composition out of the injector barrel and through the tubing to the vertebroplasty site.
The Duro-Ject and Minimix devices are quite effective in delivering compositions to vertebrae or other locations in the patient. Even so, they require a number of separate components and a number of separate actions in order to generate the composition and move it from a mixing station to an injecting station. Compositions used for vertebroplasty have been developed that cure in as little as around ten to fifteen minutes, and delays in preparing, transferring or injecting such compositions can result in lost composition, less- or ineffective vertebroplasty, or other difficulties. There is a need for devices that reduce the effort, time and number of devices required to prepare and place a vertebroplasty compositions.